1. Field of the Invention
The present invention relates to a method of recording dubbing audio in connection with recorded still pictures onto a recording medium, e.g., a rewritable DVD (Digital Versatile Disk).
2. Description of the Related Art
A disk-type recording medium such as a compact disk (CD) can store high-quality digital audio data permanently, so that it is a popular recording medium. A digital versatile disk (referred as ‘DVD’ hereinafter) has been developed as a new disk-type recording medium. A DVD can store much larger data than a CD, and thus, high-quality moving picture or audio data are recorded on a DVD for much longer time. Therefore, a DVD will be used widely in the near future.
There are three types of a DVD, DVD-ROM for read-only, DVD-R for write-once, and DVD-RAM or DVD-R/W for rewritable. For a rewritable DVD, the standardization of data writing format is in progress.
Recently, a Digital Still Camera (DSC) being capable of storing a taken picture in digital data has been developed. Such a DSC usually has a memory chip of large storage capacity so that it can take high-quality pictures and store audio data associated with the stored pictures as well. In a DSC, the taken pictures are encoded in the format of JPEG or TIFF while the audio data are encoded in the format of PCM, u-Law PCM, or IMA-ADPCM.
A DSC has a well-known file system called ‘DCF’ (Design rule for Camera File system) for recording still pictures and audio data. FIG. 1 shows an illustrative DCF. In the structure of DCF, a DCIM (Digital Camera IMages) directory exists under a root directory and many subdirectories may exist under the DCIM. Each subdirectory has 8-digit-long filename that is composed of three numeric digits and five character digits. The three numeric digits should be unique, for instance, one among 100-999, and the five character digits are arbitrarily chosen by a user. Because the three numeric digits are unique, the subdirectories can be created up to 900. A temporary directory named ‘TEMP’ is also under the DCIM.
A subdirectory, e.g., subdirectory ‘100ABCDE’ of FIG. 1 can accommodate many data files of which filename is 8-digits long. The filename is composed of four numeric digits and four character digits. While the four character digits are chosen by a user, the four numeric digits should be unique among data files if their attributes are different. The data files are still picture and/or audio files, respectively. The still picture files have an extension of ‘JPG’ or ‘TIF’ while the audio files encoded by PCM, u-law PCM or IMA-ADPCM have an extension of ‘WAV’. The filenames of the data files can be the same if their extensions are different. Therefore, when a picture file is to be dubbed with audio, a dubbed audio file can be linked with the picture file only if their filenames are made the same.
By the way, a disk video recorder (DVR), which has been developed recently, can record still pictures as well as motion pictures. If a DVR adopts its recording format and management information structure being able to improve compatibility of recorded still pictures and dubbing audio data with a DSC, a user can move or copy between a DVR and a DSC without any data conversion or any data converting tool. This will improve use convenience of the two electronic machines.
However, when adopting the recording format and management information structure to improve compatibility, a provisional DCR standard for motion picture recording must not be violated by the adoption.